M29-2 Displaying Exceesive Pressures With Light Loads

[semperfi71]

I am posting this here instead of in the reloading section because there is something wrong with this handgun.

My M29-2 with 6 inch barrel has, since I bought it, been able to handle reloads with 240 grain bullets loaded with 2400, H110, and W296 in the top-end/maximum load capacity of 21 to 21.5 grains depending on powder and bullet. No signs of excessive pressure. (flattened primers or sticking cases).

Now, with just 17.5 grains of 2400 or 17 grains of Accurate #9, and the Remington 240 JHP I am getting very flattened primers and sticking cases. The 2400 load chronoed at 1100 to 1200 fps.

The reloads are good, no mistakes there (I know we are prone to such things but I have been very diligent in this issue). Brass is once fired to twice fired. Length is correct.

I had my gunsmith clean up the forcing cone with his reamer. It showed the same problem before his work and after.

The cylinder has no endshake, the tolerances of barrel-cylinder gap and headspace are correct as to Kuhnhausen's manual. He does not offer any suggestions to cure my problem by the way.

The cylinder/bolt lockup allows a little bit of side-to-side movement but in a single, or double-action pull the cylinder locks up tight enough that the chambers and throats appear to be "true" to the bore.

The barrel is super clean. It had many years accumulation of copper wash. I soaked it a week with Hoppe's #9. All copper wash was removed.

No appearances anywhere in the bore of any kind of abnormality in the barrel or rifling.

The powders in use are good. They have produced normal reactions in other handgun loads (.357 magnum only).

The Remington bullets mike out at .430. I am going to try some other jacketed bullets, and maybe even lead.

I also have a M29-2 with the 8 3/8 inch barrel. I will try these 2400/#9 loads in it as well. If they show pressure signs there then we have THAT problem to deal with.

The Remington bullets easily slide through all six chamber throats.

Any suggestions would be appreciated. Thank you.

 

[OKFC05]

To me, this brings to mind two things:

Near-max loads in one gun may be overloads in another.

"Pressure signs" are notoriously unreliable in straight-walled pistol cartridges as a way of estimating instantaneous max pressure of a handload. Read one account of handloads tested with a transducer lab setup being up to 50% over SAAMI standards.

 

[Fishinfool]

I would try a couple factory loads thru the gun, and see if you have the same problem. That will at least tell you if it's your loads, or the gun.

Larry

 

[Leonard]

Try a non magnum primer or a different brand? Slug barrel?

 

[ScottJ]

Also, when your loads get light you can't rely on primers. What happens sometimes is the shot backs the primer out first and then as pressure builds the case comes back to join it and flattens it in the process. In a hotter load the case and primer move back together.

That's why I don't worry about flat primers unless they are joined by other signs like flow around the firing pin indentation, ironing of the headstamp or hard extraction.

But none of the above explains why you get sticking though.

Perhaps this particular 29 has headspace issues?

 

[ImprovedModel56Fan]

FIRST, shoot your handloads in your other gun. Don't even bother thinking about what MIGHT be going on until you've done that. Once you've done that, you will almost surely know whether it's the gun or the loads. I'm betting on the loads. Pull a couple of bullets and weigh the charges with somebody else's scale.

If it's the gun, I have nothing to offer.

 

[semperfi71]

Thanks for the input.

I have not slugged the bore because the handgun previously was shooting fine.

I will shoot the same loads in my other M29-2. I am also considering buying a box of factory full-load .44s. Although that is scary, if I have some kind of unknown constriction, then I might blow the gun up.

I am also going to try other bullets with the same powders and other powders if necessary.

The scale is good, I have checked it with known weights.

One thing I am curious about, and this might be a stretch. H110 and W296 are notorious for eating metal in full loads, as in flame-cutting. I am wondering if the amounts of H110 and W296 put through this handgun have somehow "workhardened" or in reverse "softened" the metal in the forcing cone. If so I am wondering if that could cause a spike in pressures. Like I said that premise is a stretch in reasoning though.

 

[tomcatt51]

One thing I am curious about, and this might be a stretch. H110 and W296 are notorious for eating metal in full loads, as in flame-cutting. I am wondering if the amounts of H110 and W296 put through this handgun have somehow "workhardened" or in reverse "softened" the metal in the forcing cone. If so I am wondering if that could cause a spike in pressures. Like I said that premise is a stretch in reasoning though.

Definitely a stretch. I'd look elsewhere. I have used AA #9 for years in 44 mag with Winchester primers and 240's, both lead and jacketed.

 

[cochise]

You mentioned cleaning the bbl very good but what about the cylinder? Have you shot any specials then went back to magnum length cases? The shorter cases leave residue, even if it was only 6 shots.

I doubt all of a sudden it would be your hand gun. I shot a "box" of my hand loads that were too hot even though the manual said it was below max. Try factory loads as mentioned. then double check your handloads. Start with the simplest items first before jumping into a "re-build" of your revolver.

Let us know what you find out.

 

[snw19_357]

I read through this quick (so didn't get everyone's response) but I see you mentioned H110/W296.

They are slow burning Magnum powders and you will get more pressure from a light load than a max load. Reduced loads with this powder can be very dangerous!

 

[tomcatt51]

I read through this quick (so didn't get everyone's response) but I see you mentioned H110/W296.

They are slow burning Magnum powders and you will get more pressure from a light load than a max load. Reduced loads with this powder can be very dangerous!

His issue is with 2400 & AA #9 loads.

 

[snw19_357]

His issue is with 2400 & AA #9 loads.

See, told you I didn't read it.

 

[GyMac]

As someone said, maybe you should slug the bore. It wouldn't be the first time a gun left the factory with the wrong bore size.

 

[semperfi71]

Thanks for all the input.

H110 and W296, in my experience with a chronograph, will, at below suggested loads show hugely erratic and very low velocities "swings". I think that's why the warning, a possible bullet lodged in the barrel and another and then.........

The bore has shot previously well so it has to be of good dimensions.

Never fired .44 Specials. I do not do this in .357s either, for that very reason, the inner "ring" of the shorter cases. When I want reduced loads I use the .44 Magnum or .357 cases and load them to the desired lower velocities.

Chambers were clean.

The starting loads I mentioned are listed in the manuals as safe starting loads.

Thanks for the input and I appreciate anything further, no matter how "off-the-wall".

This is a strange anomaly.

Here's my intent. 1) Factory loads for test, 2) Load some Unique, Bullseye, etc. (low pressure target loads) that I know are safe and load them to maximum and see the results. 3) Load other bullets with my standby loads of H110 and W296 as well as the 2400 and AA#9...it COULD be the Remington bullets although I have some old data shot with them and H110 in this gun.

I paid $400.00 for this gun in 1983. Have you priced a M29-2 (either 6 or 6 1/2 inch barrel) lately? I'd hate to have to replace the gun with another. And if I swap the barrel, could it be the cylinder instead?

I do intend to take it to my gunsmith and have him look it over again. But he wasn't home today.

 

[BruceM]

If you have no headspace/endshake issues and the chambers are indeed clean, the first thing I would do is fire a cylinder full of factory loads & try to duplicate the problem. Fire another string of the same ammo from another Smith .44 magnum in order to eliminate ammo as a problem.

Dropping sized bullets thru the chambers will tell you if you have constriction there and pushing a pure lead sized & lubed bullet thru the bore will tell you the same. If, after testing the bore and chamber throat and finding no problems or ammo problems, sticking cases in clean chambers would suggest bulged chambers to me. Usually, bulging a chamber results from firing a round which is well in excess of proof load pressures but it may be possible that multiple damaged chambers could be the result of incremental damage from repeatedly firing slightly overpressure loads. This happens often in bolt action rifles with the result being excess headspace over a period of time.

At any rate, if the guns is clean and you cannot identify any cylinder throat throat or bore anomalies, I would check for bulged chambers.

For what it's worth, cratered and/ flat primers are not effective high pressure indicators in handguns loads IMO. In rifles, that's another story.



Bruce

 

[M29since14]

Any time you have concerns about safety, never load more than one cartridge.

I would buy a box of factory loads and try a few in your other gun to be sure of what you have. Then load one in your 6-inch gun and see what happens. If that one works OK, leave the empty in the cylinder and try another one in another chamber. If it shoots OK, keep doing that until you get all the way around the cylinder and all chambers seem to check OK. If so, you know your loads are causing the trouble.

I routinely use 18.0 grains of 2400 in 44 Magnums and with any bullet of 240-gr or heavier, up to 275-gr, I never have the slightest problem. So your load would seem OK, assuming you are using standard large pistol primers.

If you cannot diagnose the problem after testing with factory loads, I would stop shooting your handloads and get a knowledgeable friend to double-check them. He may spot something you have missed. Sometimes we "see" what we are expecting to see. I know that sounds like an "I wouldn't do that," but sometimes it happens nonetheless. Have you checked your ammunition with a "maximum ammunition" gage, like the ones made by Wilson?

If factory loads do not work in your 6-inch gun but work OK in the other gun, send the gun back to S&W and let the experts figure out what is wrong.

I would appreciate knowing how this problem plays out. Please let us know. Given your description, the problem isn't obvious, so proceed with caution.

 

[Aticus]

I will be watching this thread with interest as I have a 29-2 with the same problem. In my case head space is good and the end shake is good. However I get very flattened primers with less than max loads with H-110 and 2400 behind Hornady 240 XTP's. (I don't remember the exact load but it's well below max.) My first check was to fire factory loads (Winchester 240 JHP) with the same result. I also get flattened primers with a load of 6.2 grs. of 231 behind a Suters 240 SWC. Not quite as flat but enough to be of concern. Chambers are clean when fired and extraction is easy.

I'll be watching thanks for reading.

Pecos

 

[Dragon88]

Are you using magnum primers with 2400? Alliant specifies standard primers only with this powder. I'm not saying this is the cause of your issue, but we are really grasping at straws here so I figured I'd bring it up.

 

[semperfi71]

Thanks again for the input.

Flattened primers alone are usually not a good indicator of high pressures in rifles or handguns in my experience. But sticking cases (badly) with flattened primers is.

I have shot revolvers with standard pressure loads with bulged chambers and the cases easily extracted. The most notable was a S&W M&P Brit that had been re-chambered from .38 S&W to .38 Special.

Yep, magnum primers with 2400. Elmer K. said they weren't needed and others here have reported the same. But in low velocity loads with an incremental buildup in powder levels I have never had a problem.

Shooting factory ammo will be done.

Chamber throats allow bullets to pass.

I have a Ruger Vaquero in .44 Magnum and it and the M29-2 are going to the range tomorrow. The Vaquero will be shooting the "suspect" loads and the M29-2 the factory and the new loads before.

I loaded today the Speer 240 grain JSP vice the Remington 240 grain JHP that is in the "problem" loads. Also this box is loaded with H110 that I know is good. THIS load has shot in this gun all the way to 23 grains without pressure signs...about 25 years ago.

However I noticed I loaded the Remington JHPs with 2400 years ago to about 21 grains without any issues. That's why this latest problem is rather difficult for me to understand.

Yes, it does help to have a second set of eyeballs sometimes. Today I loaded five rounds of the above H110 load with 21.5 grains of H110. Then as I went to move the scale to 22.0 grains I noticed it was set at...25.0 grains!!! I was lucky I caught that.

The scale is good. It is an Ohaus 505 purchased in 1972. I checked with several of the Speer bullets, dead on at 240 grains, + or - .5 grains.

M29since14, very good advice and I will follow through.

I will add this. I "bell" the cases just enough to allow the jacketed bullet to barely enter the case. About 1/16 or less of the base of the bullet. The bullets seem to seat without any distortion. My dies (RCBS) size the cases very tightly so that when the bullets are seated as I described there is a definite "bulge" in the forward portion of the case where the bullet finally sets. Today I loaded a case with a LOT of bell and it still bulged the tight case.

I pulled five of the suspect rounds with an inertia RCBS bullet puller. It took usually four hard strikes to get the bullets to pull.

I have been using this bullet seating technique as long as I have been reloading and have never seen a problem with it. The dies were purchased back about 1973 or so.

 

[arjay]

A couple of ideas come to mind.Have you used this particular bullet before? When you worked up these loads years ago,are you still using those same powders or are they different lot numbers?